The effect of gravel and sample diameter on water flow in soil

The effect of gravel and soil column diameter was evaluated on the flow of water in a silty loam soil. The experiment was carried out in seven columns with nominal diameters of 40, 63, 90, 110, 160, 200 and 250 mm. Two soils sampling approach were used including soil sieved by the sieve No.10 (SS) and unsieved soil (US) which has gravel. The results also compared with the field. The result show that effect of column diameter was significant (P<0.01) on cumulative infiltration, soil basic water infiltration rate and saturated hydraulic conductivity. Overlay the soil column of 110 mm had the least difference in comparison with the field data. The cumulative infiltration measured 43.33 and 44.51 cm for SS and US, respectively. The infiltration rate was 0.29, 0.32 cm/min for SS and US, respectively. It measure 0.28 and 0.31 cm/min for SS and US, respectively on saturated hydraulic conductivity. It concluded that the measured values in soil column of 110 mm in diameter for sieved soil and unsieved soil can be considered similar to field values for this soil and experiment conditions.